Please help! Merkur Scorpio Plenum swap

[coach_87]

I can't figure out why the truck keeps idling overly high and won't Rev back down after a quick blip of the throttle. Usually around 2500rpm.

I've oblonged merkur tps mounting holes so I could adjust to 0.90v at closed throttle.

I can't find vacuum leaks anywhere by spraying flammable break cleaner around anywhere I touched.

Is my map sensor seeing too much vacuum?
Maybe just a low battery issue is fooling me?

I feel like I'm missing something simple but can't see what it is.

 

[dvdswan]

did the original air cleaner have any vacuum lines hooked to it? did you plug any vacuum hoses that are metered air?

 

[coach_87]

The scorpio intake has one smaller vacuum fitting at back for the fuel regulator.
Then a larger vacuum port lower on the driver side between runners to cylinder 3 and 5, that I have ran to my brake booster.
Throttle body has two small vacuum ports, which I'm unsure which does what. Maybe one before and one after throttle blades? I have map hooked up to one that creates quite a bit of vacuum and the other that has less vacuum is run to my charcoal canister.
Maybe I should have my map on lower vacuum? And just figure out something completely different for charcoal canister?

 

[gaz]

coach,
It certainly does sound like a vacuum leak. If you can not adjust it correct, I would consider re-installing the manifold; taking a close look at the T/B, intake manifold gaskets and recheck all the vacuum connections.

ADJUSTMENT:
Completely disconnect your battery for 30 minutes, this resets your computer.

I would let it warm up to temp, without "blipping" the throttle. See how it behaves at normal operating temperature.

The computer once reset may need a some run time to get used to the new air level it's getting.

Also, once warm, I would remove your intake ducting and look at the T/B butterfly valves while idling, before and after a throttle blip, see how open they are.

 

[dvdswan]

You need to have the vacuum diagrams for both intakes and match the hoses to where each goes. does the intake manifold fit perfectly as the old intake manifold did? What I mean is it the same layout to match the gaskets?

When I did the 240 intake on my Nissan truck years ago I missed a hose from the air cleaner that was metered air. That cause a high idle just like a vacuum leak.

 

[coach_87]

Problem is I can't find a scorpio vacuum diagram. Maybe I'm searching wrong keywords but I keep failing.
I'm standing in front of it right now working on it though. So both throttle body vacuum ports apparently hit 20in/hg. Playing with the lines and vacuum gauge I can get it to high idle at 2400rpm and have good throttle response, by having map sensor to left vacuum port, gauge on right, canister unplugged. If canister in left port and gauge on right, truck rough idles 800-1000rpm and I can produce slight vacuum to even out idle.

I feel like at this point I need to just find a port than sees low vacuum for the map sensor. Hope someone can say if this is right or not. Like maybe put it in front on the throttle blades?

 

[coach_87]

Gaz,
I just had battery disconnected for couple hours while I was charging the battery.

I checked the throttle blades quite a bit cuz I had to cut down the scorpio cable to fit the ranger pedal(returns smoothly and quickly). They close fully and open fully. If I adjust the blades more open the truck just idles higher, so I believe I have that correct now.

Was blipping throttle only to try idle down. Thought maybe running it would help the computer learn but it's a bit concerning to cold start and idle that high.

dvdswan,
wouldn't the break clean method tell me if any leaks? I sprayed around and nothing. That's why I think I've got stuff hooked up wrong.

 

[alwaysFlOoReD]

@PetroleumJunkie412

 

[coach_87]

Messed with the tps a bit and now I have it idling 1100-1200rpm but its still idling rough(My phone a friend lifeline told me to use my other multimeter that has the proper function I needed).
Smells like I'm running rich now but my idle is closer. It warmed up inside the garage and still won't idle back down quickly when I blip the throttle. Only would blip quick if I unplugged vacuum to map sensor.
I have a code reader that plugs in and only code 95 shows(from a previous ecm change, no worries).

How much vacuum should my map sensor be seeing at idle?

Also how much vacuum should be at my fuel regulator?

Just trying to get this truck back to daily driver status. Couple years back I did jba headers, egr delete, upgraded heads, 88 ecm.

 

[85_Ranger4x4]

That said I did have an intake leak on my 302 right after I did the swap. It was leaking to the lifter valley so no amount of brake cleaner could get it to do anything.

 

[superj]

hook your shop vac to the intake, but use the output side of the vacuum so it forces air into the engine. than you can feel for leaks.

 

[gaz]

Coach,

Please snap a pic of the intake vacuum outputs you feel may hooked to the wrong components.

 

[coach_87]

Hooked up this way it idles at 1250rpm and when I hit the throttle it takes 8-10seconds to drop back down to idle. So right now only 3 items take vacuum from the plenum.

I just put a vacuum pump on the map sensor and it didn't hold pressure.... could that be why idling high and slow to come back down?

 

[coach_87]

Good news everyone! Seems like I needed to let it run in this configuration for a warm up cycle to let the computer learn itself again. Idle is slowing down to about 950 now and then it's not holding high rpm on throttle blip but still slow to lower after 1600rpm.

I did adjust my tps to .658. Lowest I could make it read without seeing code 23.

Now that things are where it seems they should be I might introduce timing into the situation and see how the truck likes it. Maybe that can get me back to the magical 850rpm

 

[dvdswan]

I'm probably wrong. But in the second pic that is next to the MAP that is plugged, I think that would be metered air pressure.